Question

A driver of a car travelling at 52kmh^-1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5s. Another driver going at 3kmh^-1 in another car applies his brakes slowly and stop In 10s. on the same graph paper. Plot the speed versus time graphs for the two cars, which of the two cars travelled farther after the brakes were applied?

Answer 1

initial velocity of A car u₁ = 52 kmh^-1
= 14.4 m/s.
Time taken to stop car t₁ = 5 s.
After 5s car comes to rest Initial velocity of B car, u₂ = 3Kmh^-1
= 0.833 m/s. = 0.83 m/s.
Time taken to stop car t₂ = 10s
After 10s car comes to rest.
Graph:

Area of ∆OPR = Area of ∆OSQ
When compared car A to car B, A car travelled father. After brake it travels 52 Kmh^-1